Furnace



(No Model.) v v G. A. TURNBULL 8a W. WALTERS.

FURNACE. No. 424,039. I Patented Mar. 25, 1890.

UNITED STATES PATENT OFFICE.

GEORGE A. TURNBULL AND IVILLIAM \VALTERS, OF CHICAGO, ILLINOIS.

FURNACE.

SPECIFICATION forming part of Letters Patent No. 124,039, dated March25, 1890.

Application filed June l2, 1889.1 Serial No. 3l4 .065. (No model.)

To all whom it may concern;

Be it known that we, GEORGE A. TURNBULL and WILLIAM WALTERS, citizens ofthe United States, residing at Chicago, in the county of Cook and Stateof Illinois,have invented certain new and useful Improvements inFurnaces, of which the following is a specification.

Ourinvention relatest'oimprovementsinfurnaces in which the atmosphere isintroduced into a chamber or compartment in which itis heated before itpasses to the fire; and the 7.

objects of our improvements are, first, to so construct and arrange theair-heating chamber and the flues or passages admitting air to the sameor permitting its escape therefrom that the heating of the air thereinwill separate the nitrogenous gas from the oxygen and allow thenitrogenous gas to escape and pass 0E through the flues'and out of thechimney and conduct the oxygen up through the fire, and, second, toprovide means for admitting air to the air-heating chamber through fluesin the grate-bars in such manner as to keep the bars comparatively cool,and thereby enable them to better resist the action of the fire uponthem. These objects we have attained in the furnace constructed asillustrated in the accompanying drawings, in which Figure 1 is alongitudinal vertical section of the furnace,the boiler portion beingshown in side elevation. Fig. 2 is a transverse vertical section throughthe fire-box.

In the drawings, A designates the brickwork of the furnace, and B theboiler for generating steam for heating or power. The boiler issupported by the brick-work in the ordinary manner.

C is the fire-box,placed under the front end of the boiler and leavingan opening 0 for introducing the fuel closed by a door 0'. From thefire-box there is a flue or passage D for the products of combustion topass under the boiler and out through the boiler-fines d to the chimneyor Smokestack D, which are of ordinary construction.

E is the air-heating chamber, which is arranged beneath the fiue D andseparated therefrom by a metal plate 6, which is supported at its sideedges by being built in the side walls or supported thereon so as toform a covering for said air heating chamber. The front side of theplate is built in or supported on a transverse partitionE of thebrick-work at the rear of the fire-box. At the rear of the air-heatingchamber there is another transverse partition E which comes up nearly tothe said plate 6 at the rear end thereof, leaving a passage or flue e ator near the top of said chamber, which communicates with the flue D. Atthe front of the air-heating chamber there is a flue or passage (2through the transverse partition E at or near the bottom of the saidchamber, which leads into the ashpit G under the fire-box.

The fire-grate is composed of hollow bars F, resting on the front wallof the brick-work and supported. at their rear ends by the partition E.The passagesf through the hollow grate-bars open the way from theoutside of the furnace into the air-heating chamber for air to pass intosaid. chamber near thetop, immediately under the metal plate 6.The-brickwork is provided with suitable openings, with doors G,forcleaning the furnace.

Dampers are provided at H and connected with cranks h upon the outsideof the-brickwork for regulating the draft by partially or wholly closingthe passages e 6 The operation is as follows: A fire being started inthe fire-box C will cause the air to pass into the ai r-heatin g chamberthrough the openings through the hollow grate-bars, and thence outthrough the passage 6 and up between the bars to the fire. The plate ewill be thereby presently heated, so as to heat the air in said chamberand cause the same to be partially and to alarge degreeseparatedinto itselements-mitrogen and oxygenthe nitro enous portion remaining near thetop of will be drawn from the bottom portion of said chamber through thepassage 6 to the fire, thereby increasing the combustion. As the coolair passes into the said chamber through the hollow of the grate-bars ittends to keep them cool, so that they can better resist the action ofthe fire. The eifect of separating the air into its elements by means ofthe heatin g-ehamber provided with the passage at the rear near the topand the passageto the fire near the bottom would be the same if the airwere admitted to the said chamber through openings at the sides of thefurnace; but we prefer to introduce the air through the hollowgrate-bars for the purpose of protecting said bars from the intense heatwhich is caused by the increased proportion of oxygen thus created inthat part of the atmosphere that passes through the fire.

()ur invention does not include a series of separate pipes placed underthe grate-bars in close proximity to the fire for the purpose of heatingair, but in such construction and arrangement of the grate-bars belowthe firebox, as willpermit thecool air from the outside to pass throughthe hollow of the gratebars and completely under the fire-box beforepassing into it, and thereby tendto keep the gratebars cool andproteetthem from the heat, as described.

Having thus described our invention, what with said fiue and a, passageat the front near the bottomcommunicating with the ash-pit under thefire-grate, substantially as and for the purpose specified.

2. In a furnace, the combination, with the rear thereof, having apassage at its front lower part into said chamber under the firebox, anda grate composed of hollow gratebars forming passages from the outsideof said furnace under the fire into said hotair chamber, and thencethrough the passage 5 5 at the front lower part thereof into saidchamber,under the fire-box, and up through the fire, as specified.

4. A furnace consisting of the fire-box, the flue for the products ofcombustion, the airheating chamber having the passages at the upper rearfront and lower front part thereof,

B. F. HEAD. FRANK NORRAK.

